author: Dr. Kevin Curran
Background on echinacea
Echinacea refers to a genus of purple flowering plants from the sunflower family. The common name for echinacea is ‘purple coneflower’ as this showy perennial grows up to 2 feet in height and produces bright, purple petals.
The plant is native to the Great Plains region of the United States. In the 17th century, as early American settlers arrived in the Great Plains, they observed the Native Americans (Dakota, Sioux, Pawnee) treating flu, influenza, sepsis and wounds with a concoction made from a purple, daisy-like flower. The settlers quickly learned the immune enhancing benefits of the purple coneflower and echinacea was shipped back to Europe.
This past century, scientists have published more than 800 journal publications on the chemistry, pharmacology, and clinical uses of echinacea. The majority of these reports explore the effectiveness of echinacea for colds and other infections.
In this article we review the science behind these health claims. At the end of the page, we discuss the factors involved when choosing an echinacea supplement.
Echinacea for colds
The common cold is cited as the most frequent disease in Western civilization (Jawad, 2012). Everyone knows there is no cure for the common cold, but is it reasonable to take echinacea to help with cold symptoms?
The echinacea plant is commonly used as an immune system enhancer (Foster, 1991). In theory, an immune system enhancer helps your own immune system challenge and fight off an infection.
Many clinical trials have been conducted on the efficacy (success rate) of using echinacea for colds or the flu. The results of these trials are often conflicting. However, in 2007, a meta-analyses was published and the overall conclusion stated there is a modest benefit to the use of echinacea for colds (Shah, 2007).
A meta-analyses is a cumulative summary of multiple high-quality clinical trials. This report claims if you begin taking echinacea at the first instance of a cold symptom, you will likely shorten the time period that you are sick and there’s a reasonable chance you will also reduce the severity of the symptoms.
Echinacea decreased the odds of developing the common cold by 58% and, furthermore, echinacea use reduced the duration of a cold by 1-4 days. In conclusion, published evidence supports echinacea’s benefit in decreasing the incidence and duration of the common cold (Shah, 2007).
It should be noted that another meta-analyses was published in 2014 and the overall conclusions were less positive (Karsch-Völk, 2014). These authors reported only weak benefits for cold treatment and just small effects for cold prevention.
In our opinion, much of this scientific inconsistency is due to researchers using different echinacea species and different plant parts (stems, roots or flowers) in their experimental design. A large scale review of trials using similar echinacea plant material would likely yield more conclusive results.
Recent echinacea news
The echinacea plant continues to be an incredibly popular herbal supplement. The American Botanical Council (ABC) published their 2014 report of the top-selling medicinal plants in the United States. Echinacea sales reached more than 50 million dollars, this is a 79% increase over previous year sales. The only other medicinal herbs to sell more than echinacea were cranberry and horehound. We will update this section as soon as the 2015 ABC report is made public.
Recent clinical news
A recent clinical trial has been performed that is worth reporting (Rauš, 2015). A group of European scientists were curious whether echinacea was as effective as Tamiflu for treating influenza (commonly called ‘the flu’). Tamiflu (oseltamivir) is a leading remedy for treating/reducing flu symptoms. The group performed a parallel, double-blind study on 473 patients who were showing early flu-like symptoms. Some of the patients were treated with Tamiflu while another group received echinacea. After 5 days, the rate of recovery from illness was 50.2% in the echinacea group, while the recovery rate in the tamiflu group was 48.8%. The authors of this study conclude that echinacea is as effective as Tamiflu for the early treatment of influenza. The authors also observed less side effects with the echinacea treatment group (Rauš, 2015).
Based on this study, it appears echinacea is a more appealing option than Tamiflu.
Factors to consider when choosing an echinacea supplement
There is a lot of variation in the content of different echinacea supplements. When you choose an echinacea supplement you want to consider these factors:
- Which plant species are used? (E. purpurea, E. pallida or E. augustifolia?)
- Which plant parts are included? (roots, stems, leaves, seeds, flowers?)
There are three popular species of echinacea: E. purpurea, E. pallida and E. augustifolia. Different companies use different echinacea species and some use a combination of all three species. The strongest evidence in support of echinacea for colds, the flu or upper respiratory infections comes from clinical studies of the species E. purpurea (WebMD). Clinical studies of E. angustifolia and E. pallida are promising but, overall, show less convincing results. Therefore, we recommend looking for supplements that contain mostly E. purpurea.
Each part of the echinacea plant contains different biologically active compounds. Some supplements use only echinacea root, others use the aerial portion (stems, flowers, leaves). We recommend a supplement that includes both the root and aerial parts.
In summary, we recommend an echinacea supplement that focuses on a combination of the root and aerial parts from E. purpurea.
Lastly, it should be noted that allergic reactions to echinacea are rare, however, if you are allergic to ragweed or other plants from the sunflower family, you should be extra cautious when using echinacea for colds.
Remember to bookmark this page! We will update this article as new clinical data is published on the health benefits of echinacea.
Dalby-Brown, Lea, et al. “Synergistic antioxidative effects of alkamides, caffeic acid derivatives, and polysaccharide fractions from Echinacea purpurea on in vitro oxidation of human low-density lipoproteins”. Journal of agricultural and food chemistry 53.24 (2005): 9413-9423.
Foster S, “Echinacea Nature’s Immune Enhancer”, Healing Arts Press, Rochester, Vt, USA, 1991.
Gorski, J. Christopher, et al. “The effect of echinacea (Echinacea purpurea root) on cytochrome P450 activity in vivo.” Clinical Pharmacology & Therapeutics 75.1 (2004): 89-100.
Jawad M., et al. “Safety and efficacy profile of Echinacea purpurea to prevent common cold episodes: a randomized, double-blind, placebo-controlled trial.”Evidence-Based Complementary and Alternative Medicine 2012 (2012).
Karsch-Völk M, Barrett B, Kiefer D, Bauer R, Ardjomand-Woelkart K, Linde K. Echinacea for preventing and treating the common cold. Cochrane Collection. (2004) http://www.cochrane.org/CD000530/ARI_echinacea-for-preventing-and-treating-the-common-cold.
Rauš, Karel, et al. “Effect of an echinacea-based hot drink versus Oseltamivir in influenza treatment: A Randomized, double-blind, double-dummy, multicenter, noninferiority clinical trial.” Current Therapeutic Research 77 (2015): 66-72.
Shah SA, Sander S, White CM, Rinaldi M, Coleman CI. “Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis”. Lancet Infect Dis. (7) (2007) 473-480.